I clean my sizing dies evertime I am fixing to use it, if I know the time before a few cases went through it.

I use " carburetor" cleaner spray and I know alot of people use the same.

If the die comes apart then take it apart and use Q-tips.

I also use rubbing Alchol, works real good. But on Lee Dies they need " carburetor" cleaner blown up there, you cant get all the gunk out of a die if you never or cant take it apart.

That Quick scrub cleaner for guns will work also, its about the same as carburetor cleaner. Like mentioned above you need to oil the dies after cleaning.

Troy